The present invention relates to robotic assembly of wire harnesses, and, more particularly, to a contact-independent double pinch-push contact insertion end-effector for use in wire harness assembly.
Fully automatic production is a sought-after goal in cost-effective wire harness assembly. Such assembly preferably is achieved by means of a manipulable mechanism which can insert contacts of varying styles into connectors and which mechanism is articulable by means of a robot arm.
Insertion tools which are typically used when performing a contact insertion are contact dependent, i.e., dedicated to a particular contact style. Furthermore, the force required to insert a contact into a connector typically ranges from below one pound up to six pounds where the insertion force is dependent on the contact and connector combination used. Grommetless connectors have less resistance to contact insertion than do grommet connectors. Therefore lower insertion forces are encountered when performing a contact insertion into a grommetless connector (typically less than one pound) than into a grommet connector (typically greater than four pounds). Therefore, it is desirable that the same insertion tool be operable for both low and high insertion force applications, independent of contact style.
Such a versatile insertion tool preferably should be able to perform contact insertions for wires prepared by attaching crimp contacts, such as per MIL-C-39029, where prepared wire gauges range from 16 to 24, with an insulation wall thickness of 0.003 to 0.010 inch.
Because it is not possible to have a fully sequenced contact insertion routine for all connectors, the insertion tool must have the capability to perform random contact insertions. A random contact insertion involves interference with the wires of previously inserted contacts during positioning of the insertion mechanism to effect such random contact insertion.
Furthermore, it is additionally desirable that the insertion tool be able to perform a tug test. A tug test is performed by pulling on the wire of the inserted contact to verify proper seating of the contact. A properly seated contact is locked into the connector and cannot be removed unless an extraction tool is used. It is also desirable that the tug test capability be available as an aid during the contact insertion process, such as for force monitoring.